Silicone vitamin esters

ABSTRACT

The invention discloses novel series of silicone esters, which are useful as antioxidants on skin. The products are produced using for a variety of hydroxyl containing actives such as vitamin A (retinol), vitamin A-2, and vitamin E. Compounds of the invention are prepared by the esterification of (a) a specific silicone methyl ester and (c) a hydroxyl functional active. The esters of the present invention allow for the formulation of personal care products in which the “active” can be formulated into a variety of solvents without the loss of activity.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention discloses novel series of silicone esters which are usefulas antioxidants on skin. The products are produced using for a varietyof hydroxyl containing actives such as vitamin A (retinol), vitamin A-2,and vitamin E. Compounds of the invention are prepared by theesterification of (a) a specific silicone methyl ester and (c) ahydroxyl functional active. The esters of the present invention allowfor the formulation of personal care products in which the “active” canbe formulated into a variety of solvents without the loss of activity.

By hydroxyl, functional active is meant a vitamin, co-vitamin, or othermaterial known to effect a change to the hair or skin, which contains ahydroxyl group or hydroxyl groups.

2. Arts and Practices

The personal care market is a very diverse market segment, whichincludes a number of products designed to protect the skin and hair fromthe degradation effects of sunlight and environmental distress caused byfree radicals.

In addition to protecting the hair and skin by acting as antioxidants,there is a need for products that improve the condition of the hair,skin nails, and lips. The desirable functions include but are notlimited to; barrier properties, remoisturization, softening, andconditioning.

One of the most important functions of human skin is the protectionagainst adverse environmental factors. Environmental factors likeexposure of the skin to sun, cold or heat adversely affects the skin andminimizes the barrier property of the skin. Additionally, theapplication of many cosmetic products or use of soap on the skin removesthe fatty layer of the skin. It is therefore highly desirable to replacethe barrier properties, which are removed from the skin. Lipids andother oily materials added to the skin improve the natural barrierproperties of the skin and hair the skin retain moisture and feel soft.If a suitable delivery system is used Vitamin A, Vitamin A-2, andVitamin E are excellent materials for use as moisturizing and barriercréme applications. These materials are very difficult to deliver fromaqueous environment. One attempt to deliver these materials to the skinhas been to make emulsions of these oils in water. This is done byselecting surface-active agents, which will emulsify the hydroxyl activeinto small droplets, which are surrounded by the surface-active agent inwhat are called micelles. The resulting emulsion resembles milk andcontains the emulsified hydroxyl active. The difficulty with thisapproach is that the material present in the micelle is deposited veryinefficiently onto the hair and skin since the micelle must break todeliver the oil. Since the majority of the micelles do not break, themajority of the active is rinsed off and ends up in the drain. Anotherapproach has been to make derivatives of these oily materials. There hastherefore been a long felt need for materials, which could beincorporated into personal care products, which deliver vitamins to theskin.

We have discovered that the incorporation of Vitamin A, Vitamin A-2, andVitamin E, into a silicone ester in relatively low concentrationsresults in polyesters which can be made soluble in many differentsolvents and which give the beneficial properties of the cholesterol orlanolin to the skin and hair. In short, low concentrations of theseesters by virtue of their substantivity to hair and skin will provideoutstanding protection from oxidation and free radical attack as well asmoisturizing properties in many varied personal care formulations.Activity is seen at as low as 0.1%.

U.S. Pat. No. 5,210,133 to O'Lenick Jr., issued May 1993 discloses“novel series of silicone polyesters which are useful as deliverysystems for a variety of hydroxyl containing active such as lanolin,cholesterol, dihydrocholesterol, Vitamin A, Vitamin D-2, Vitamin D-3,Vitamin D-4, Vitamin E, and panthenol.

These undesirable by-products alter the properties of the compound. Thecross-linked silicone molecule can cause gellation of the product. Thevitamin cross-linked to another vitamin lacks water solubility andtherefore results in products, which split into two phases. Theseproblems have resulted in lack of commercial success of the products. Itwas not until the current invention was it understood that the reactionof a silicone methyl ester with the hydroxyl vitamin that clearhomogeneous cosmetically acceptable products could be produced that donot split into two phases.

THE INVENTION

Object of the Invention

It is the object of the present invention to provide a series of novelsilicone esters, which contain within the molecule an “active”functionality. The selection of the proper methyl ester silicone resultsin the ability to prepare products, which have solubility in a widerange of solvents and are free of undesired by products encountered inthe polyester chemistry disclosed in U.S. Pat. No. 5,210,133.

It is another objective of the current invention to provide a method oftreating hair and skin with these esters. The process for treating thehair and skin comprises the contacting of the hair or skin with aneffective conditioning amount of the silicone ester. The siliconeportion of the molecule is substantive to the substrate, hair, and skinand binds there. The beneficial effect of the active is enhanced sincethe silicone delivers the active to the surface of the hair or skin.This prolonged intimate contact allows for enhanced performance by theactive.

It is still another objective of the current invention to provide aproduct, which conditions, remoisturizes and softens skin but does has amarked reduction in the irritation to the skin of lanolin orcholesterol. The incorporated of the active into the polyester resultsin the minimization or elimination of irritation to eye and skin.

SUMMARY OF THE INVENTION

The present invention relates to a series of novel silicone estercompounds. The compounds by virtue of the Vitamin A, Vitamin A-2, andVitamin E, offer outstanding antioxidant properties when applied to theskin additionally provide refatting, moisturization, conditioning andsoftening.

The ester compounds of the invention are prepared by the esterificationof a very specific silicone methyl ester directly with a hydroxylvitamin, producing a silicone alkyl ester heretofore unknown in the art.

it will be clearly understood that the silicone compounds may containone or many a hydroxyl groups, ad the active the lanolin and orcholesterol contains only one hydroxyl group. This means that thepreparation of the compounds of the present invention differ in anothersubstantial and unexpected way from the compounds of U.S. Pat. No.5,3210,133 to O'Lenick Jr, issued May 1993. The '133 patent is made byreacting a diacid with a silicone compound containing a hydroxyl groupand a vitamin containing a hydroxyl group. In addition to the problemalready described wherein with the both sides of the diacid react withtwo different silicone molecules or different two vitamin molecules,producing upwards of 45% undesired insoluble materials, there is aproblem when there is more than one hydroxyl group present in thesilicone molecule. The '133 patent discloses a situation wherein thereare multiple hydroxyl groups on silicone. In this case, a crosslinkingof the diacid and multi-hydroxyl silicone occurs forming an insolublegel. The compounds of the present invention overcome this problem, sinceno diacid is used.

DETAILED DESCRIPTION OF THE INVENTION

As stated the ester compounds of the invention by are prepared by thereaction, a methyl undecylenate substituted silicone with a hydroxylvitamin. The methyl undecylenate silicone may optionally contain alkylgroups, and/or alkoxy groups.

Reactant Silicones useful in the reparation of the compounds of thepresent invention conform to the following structure:

and are reacted with hydroxyl vitamins R¹-OH to produce the compounds ofthe present invention:

wherein:

a, b and c are independently integers ranging from 0 to 20;

d is an integer ranging from 5 to 33.

g is an integer ranging from 0 to 1,000

h is an integer ranging from 1 to 20;

i is an integer ranging from 0 to 20;

k is an integer ranging from 0 to 20;

R¹ is selected from the group consisting of

and

R² is H or CH₃.

The hydroxyl functional actives all are part of a class of naturalproducts, which can be collectively called actives, since they have abeneficial effect when applied to the hair or skin.

Hydroxy-vitamin Examples Example A—Vitamin A

Vitamin A is 3,7dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2,4,6,8-nontetraen-1-ol.It is a well-known commercially available material. The structure of

R¹ is:

Example B—Vitamin A-2

Vitamin A-2 is 3,4 didehydroretinol. It is a well-known commerciallyavailable material.

The structure of R¹ is:

Example C—Vitamin E

Vitamin E is 2,5,7,8-tetramethyl-2-(4′,8′,12′-trimethyl tridecyl)-6chromanol also called alpha tocopherol. It is a naturally occurringvitamin. It is a well-known commercially available material. R¹ is:

All these hydroxyl active materials are well known and the structuresare documented in many textbooks. One reference book is the Merck IndexEleventh Edition published in 1989.

PREFERRED EMBODIMENT

In a preferred embodiment R¹ is

In a preferred embodiment R¹ is

In a preferred embodiment R¹ is

In a preferred embodiment, R¹ is i and k are each 0.

In a preferred embodiment, R¹ is i is 0.

In a preferred embodiment, R¹ is k is 0.

In a preferred embodiment R¹ is i and k range between 1 and 20.

EXAMPLES SILICONE COMPONENT

The silicone components of the present invention are all available formSiltech LLC Dacula Ga. They are items of commerce prepared by methodsknown to those skilled in the art.

wherein;

a, b and c are independently integers ranging from 0 to 20;

d is an integer ranging from 5 to 33;

g is an integer ranging from 0 to 1,000

h is an integer ranging from 1 to 20;

i is an integer ranging from 0 to 20;

k is an integer ranging from 0 to 20.

Class 1

(In this class the values of both i and k are each 0, therefore a, b, c,d, e, f are not present)

Examples 1–7

Example g h 1 0 1 2 25 5 3 50 5 4 75 10 5 250 10 6 500 15 7 1000 20

Class 2 (In this class the value of k is 0)

Examples 8–14

Example g h i a b c R² 8 0 1 1 0 0 0 H 9 25 5 5 5 5 5 H 10 50 5 5 10 2 0CH₃ 11 75 10 10 0 0 0 CH₃ 12 250 10 10 10 10 10 H 13 500 15 15 10 10 10CH₃ 14 1000 20 20 20 20 20 H

Class 3 (In this class the value of i is 0.)

Examples 9–21

Example g h k d 15 0 1 1 5 16 25 5 10 9 17 50 5 10 17 18 75 10 5 17 19250 10 5 11 20 500 15 20 33 21 1000 20 15 11

Class 4

(In this class the value of k and i are at least 1, therefore allelements are present)

Examples 22–28

Example g h i k a b c R² d 22 0 1 1 20 0 0 0 H 11 23 25 5 10 5 10 10 10CH₃ 9 24 50 5 5 1 2 2 2 H 33 25 75 10 10 4 5 10 5 H 11 26 250 10 5 10 2020 20 CH₃ 11 27 500 15 20 10 5 10 10 H 33 28 1000 20 15 20 5 1 5 CH₃ 11

General Reaction Conditions

The esterification can be run without catalyst; however, when nocatalysts used reaction rates are less efficient. Standardesterification catalysts are generally used at concentrations of between0.05% to 0.50% with a preferred range of 0.1% to 0.3%. Catalysts whichare effective include but are not limited to; sulfuric acid, p-toluenesulfonic acid, methane sulfonic acid, tin metal, zinc metal, titaniummetal, organo titianates, organo tin compounds, organo zinc compounds,zinc oxide, magnesium oxide, calcium oxide, etc. The most preferredcatalyst is stannous oxylate. The reaction is conducted at between 140and 240° C. under an inert nitrogen blanket. The nitrogen blanketpreserves the color. Preferred temperature range is between 150 and 200°C. Water is removed from the reaction, which is done using a nitrogensparge or vacuum.

Example 29

Into a suitable round bottom, three neck flash equipped with a DeanStark trap, a thermometer and a nitrogen sparge is added 494.0 grams ofsilicone compound (example 1), 0.25% by weight of the total batchcharged of stannous oxylate and 286.0 grams of Vitamin example A. Thereaction mass is blanketed with nitrogen, and heated to 180 and 200° C.Once the reaction temperature reaches 150° C. water begins to boil offand is collected in the Dean Stark Trap. Within four to five hours, thetheoretical water is collected off and the acid value is very low. Theproduct is used without additional purification.

Example 30–57

Example 29 is repeated only this time the specified amount of thespecified silicone reactant is substituted for the silicone example 1,and the specified amount of the specified vitamin is substituted for theVitamin Example A. The same reaction procedure is followed.

Silicone Compound Vitamin Compound Example Example Grams Example Grams30 2 675.2 A 286.0 31 3 1045.2 B 284.0 32 4 836.6 C 431.0 33 5 2131.6 A286.0 34 6 2740.0 B 284.0 35 7 3970.0 C 431.0 36 8 422.0 A 286.0 37 91536.8 B 284.0 38 10 1703.6 C 431.0 39 11 832.2 A 286.0 40 12 3730.4 B284.0 41 13 4295.0 A 286.0 42 14 7032.0 C 431.0 43 15 865.0 B 284.0 4416 820.6 C 431.0 45 17 1333.3 A 286.0 46 18 980.5 B 284.0 47 19 222.1 C431.0 48 20 2931.0 A 286.0 49 21 4015.0 B 284.0 50 22 1401.0 C 431.0 5123 4038.6 A 286.0 52 24 1968.0 A 286.0 53 25 2049.0 B 284.0 54 26 3977.0C 431.0 55 27 4667.0 A 286.0 56 28 4414.0 B 284.0

Applications Examples

The compounds of the present invention are applied to the skin in avariety of formulations. The proper selection of the correct vitaminresults in optimizing the antioxidant/anti-free radical protection.

Optimization of the silicone polymer results in optimizing thesolubility of the material.

Using class 1 silicone reactants, since the values of both i and k areeach 0, the resulting antioxidant activity is seen in a silicone solubleproduct. There is neither alkoxy (water-soluble) nor alkyl (fattysoluble) groups.

Using class 2 silicones, water solubilizing groups have been introduced.This results in products having a better partition coefficient inaqueous phases, and consequently delivery of the antioxidant protectingproperties is improved from the aqueous phase.

Using Class 3 silicones, the solubility in fatty oils is increased. Thisallows for delivery of antioxidant properties from fatty oils, estersand other mineral oil soluble systems.

Finally, Using Class 4 silicones, there are groups rendering solubilityin silicone oil, mineral oil and water. This allows for delivery ofantioxidant properties a variety of phases, since the compounds willpartition in all phases.

As can be readily seen, the compounds of the present invention allow awide degree of formulation latitude for making personal care products.

While the illustrative embodiments of the invention have been describedwith particularity, it will be understood that various othermodifications will be apparent to and can be readily made by thoseskilled in the art without departing from the spirit and scope of theinvention. Accordingly, it is not intended that the scope of the claimsappended hereto be limited to the examples and descriptions set forthhereinabove but rather that the claims be construed as encompassing allthe features of patentable novelty which reside in the presentinvention, including all features which would be treated as equivalentsthereof by those skilled in the art to which the invention pertains.

IN THE SPECIFICATIONS

Reactant Silicones useful in the reparation of the compounds of thepresent invention conform to the following structure;

and are reacted with hydroxyl vitamins R¹-OH to produce the compounds ofthe present invention:

wherein:

a, b and c are independently integers ranging from 0 to 20;

d is an integer ranging from 5 to 33.

g is an integer ranging from 0 to 1,000

h is an integer ranging from 1 to 20;

i is an integer ranging from 0 to 20;

k is an integer ranging from 0 to 20;

R¹ is selected from the group consisting of

and

1. A silicone vitamin ester conforming to the following structure;

wherein; a, b and c are independently integers ranging from 0 to 20; dis an integer ranging from 5 to 33; f is an integer ranging from 2 to12; g is an integer ranging from 0 to 1,000; h is an integer rangingfrom 1 to 20; i is an integer ranging from 0 to 20; k is an integerranging from 0 to 20; R¹ is selected from the group consisting of

and

R² is H or CH₃.
 2. A silicone ester of claim 1 wherein R¹ is


3. A silicone ester of claim 1 wherein R¹ is


4. A silicone ester of claim 1 wherein R¹ is


5. A silicone ester of claim 2 wherein i and k are each
 0. 6. A siliconeester of claim 2 wherein i is
 0. 7. A silicone ester of claim 2 whereink is
 0. 8. A silicone ester of claim 2 wherein i and k range between 1and
 20. 9. A silicone ester of claim 3 wherein i and k are each
 0. 10. Asilicone ester of claim 3 wherein i is
 0. 11. A silicone ester of claim3 wherein k is
 0. 12. A silicone ester of claim 3 wherein i and k rangebetween 1 and
 20. 13. A silicone ester of claim 4 wherein i and k areeach
 0. 14. A silicone ester of claim 4 wherein i is
 0. 15. A siliconeester of claim 4 wherein k is
 0. 16. A silicone ester of claim 4 whereini and k range between 1 and 20.